Radiographic imaging substrate, radiographic imaging apparatus, and radiographic imaging system

ABSTRACT

A radiographic imaging apparatus, comprising: a photoelectric conversion substrate including a pixel area where there are arranged a plurality of pixels each formed of a photoelectric conversion element and a switching element connected to the photoelectric conversion element in a matrix formed on an insulating substrate, a bias line for applying a bias to the photoelectric conversion element, a gate line for supplying a driving signal to the switching element, and a signal line for reading electric charges converted in the photoelectric conversion element; a wavelength conversion element for converting radiation to light that can be detected by the photoelectric conversion element, the wavelength conversion element being disposed according to a region including the pixel area; and connection wiring having a photoelectric conversion layer connected to at least a plurality of lines of an identical type of the bias line, the signal line, and the gate line, wherein at least a part of the connection wiring is arranged between the region on the insulating substrate and an edge of the insulating substrate. With this arrangement, it becomes possible to provide a panel for a radiographic imaging apparatus and a radiographic imaging apparatus free from deterioration in device performance and device destruction caused by a static electricity even if a substrate is electrically charged in a manufacturing process.

CROSS-REFERENCE TO RELATED APPLICATIONS

This application is a divisional of U.S. patent application Ser. No.11/147,182, filed Jun. 8, 2005, now U.S. Pat. No. 7,205,547, and claimsbenefit of the filing date of that application, and priority benefit ofthe filing date of Japanese patent application no. 2004-177009, filedJun. 15, 2004. The entire disclosure of each of those prior applicationis incorporated herein by reference.

BACKGROUND OF THE INVENTION

1. Field of the Invention

The present invention relates to a photoelectric conversion substrate, aphotoelectric converter, a radiographic imaging substrate, and aradiographic imaging apparatus applied to a medical diagnostic imagingsystem, a non-destructive inspection device, a radiographic analyzer, orthe like. It is assumed in this specification that radiation includeselectromagnetic waves including visible light, X rays, alpha rays, betarays, and gamma rays.

2. Description of the Related Art

As a conventional typical radiographic imaging apparatus, there is aradiographic imaging apparatus constructed of a combination of aradiographic imaging substrate, on which there are arranged opticalsensors of MIS-TFT structure each formed of an MIS-type photoelectricconversion element and a switching TFT, and phosphors for convertingradiation to visible light. This type of radiographic imaging apparatusis disclosed in U.S. Pat. No. 6,075,256.

FIGS. 13, 14, and 15 show a schematic diagram, an equivalent circuitdiagram, and a plan view of a conventional radiographic imagingapparatus, respectively. FIGS. 16 and 17 show a cross section of asingle pixel and an enlarged view of a portion close to a cut section ofthe radiographic imaging substrate.

References P11 to P44 designate photoelectric conversion elements orother semiconductor conversion elements and references T11 to T44designate thin film transistors (TFTs), and each pair of them forms apixel. While a pixel area 2 of 4×4 pixels is shown here, for example,1000×2000 pixels are practically arranged on a radiographic imagingsubstrate (insulating substrate) 1.

As shown, the photoelectric conversion elements P11 to P44 are connectedto common bias lines Vs1 to Vs4 and a readout device applies a givenbias to them. The respective gate electrodes of the TFTs are connectedto common gate lines Vg1 to Vg4 and a gate drive unit makes an ON-OFFcontrol of the TFT gates. Source or drain electrodes of the TFTs areconnected to common signal lines Sig1 to Sig4 and Sig1 to Sig4 areconnected to the readout device.

X rays emitted to a subject is attenuated by and passes through thesubject and is converted to visible light in a phosphor layer 19arranged via a adhesive layer 18 shown in FIG. 16. Then, the visiblelight is incident on the photoelectric conversion elements and convertedto electric charges. These charges are transferred to signal lines viathe TFTs by means of gate drive pulses applied by a gate drive unit 4and then read out to the outside by a readout device 5. Thereafter, thecommon bias lines remove residual charges that have been generated inthe photoelectric conversion elements, but have not been transferred.

The conventional radiographic imaging apparatus has a radiographicimaging substrate 1 cut in a cut section indicated by a dashed line inFIG. 17, with the signal lines and the bias lines connected to thereadout device 5 and the gate lines connected to the gate drive unit 4via a printed circuit board such as tape carrier packages (TCPs) 6 and7, respectively. It is assumed here that TCP-A6 is a TCP connected tothe readout device 5 and that TCP-D7 is a TCP connected to the gatedrive unit 4.

A layer structure is shown in FIG. 16. An MIS-type photoelectricconversion element is formed of a under electrode (first electrode layer11), an insulating layer (first insulating layer 12), a photoelectricconversion layer (first semiconductor layer 13), a hole blocking layer(doping semiconductor layer 14), and an upper electrode (secondelectrode layer 15), with the under electrode (first electrode layer 11)connected to a TFT source-drain electrode (second electrode layer 15).The TFT includes a gate electrode (first electrode layer 11), a gateinsulating layer (first insulating layer 12), a semiconductor layer(first semiconductor layer 13), an ohmic contact layer (dopingsemiconductor layer 14), and a source-drain electrode (second electrodelayer 15). Each Vg line and each Sig line are connected to the electrodelayer where the TFT gate electrode is formed and to the layer where thesource-drain electrode is formed, respectively. Moreover, thephotoelectric conversion element and the TFT are coated with andprotected by a second insulating layer 16 and an organic protectivelayer 17. It should be noted here that the first semiconductor layer 13is formed of an intrinsic semiconductor and that the dopingsemiconductor layer 14 is formed of an n- or p-type semiconductor towhich impurities such as phosphorus or boron have been introduced.

SUMMARY OF THE INVENTION

In recent years, TFT panels can be produced in large quantities due todevelopments in technologies of manufacturing liquid crystal panelsusing TFTs and the expansion of the fields into which there have beenintroduced area sensors having photoelectric conversion elements (forexample, am X-ray imaging apparatus).

At the same time, a radiographic imaging apparatus has a characteristicof subjecting minute signals to digital conversion and graphicallyoutputting them, unlike the liquid crystal panels.

Therefore, if a substrate is electrically charged in a manufacturingprocess, and for example, a potential difference occurs between a signalline and a gate line, a Vth shift occurs in a readout TFT and therebyminute signals cannot be read out.

In case of a large potential difference in the above condition, itcauses device destruction and thus leads to deterioration of a yield ina manufacturing line for the mass production.

The present invention provides a radiographic imaging substrate and aradiographic imaging apparatus free from deterioration in deviceperformance and device destruction caused by a static electricity evenif a substrate is electrically charged in a manufacturing process.

According to one aspect of the present invention, there is provided aradiographic imaging apparatus, comprising: a photoelectric conversionsubstrate including a pixel area where there are arranged a plurality ofpixels each formed of a photoelectric conversion element and a switchingelement connected to the photoelectric conversion element in a matrixformed on an insulating substrate, a bias line for applying a bias tothe photoelectric conversion element, a gate line for supplying adriving signal to the switching element, and a signal line for readingelectric charges converted in the photoelectric conversion element; awavelength conversion element for converting radiation to light that canbe detected by the photoelectric conversion element, the wavelengthconversion element being arranged according to a region including thepixel area; and connection wiring having a photoelectric conversionlayer connected to at least a plurality of lines of an identical type ofthe bias line, the signal line, and the gate line, wherein at least apart of the connection wiring is arranged between the region on theinsulating substrate and an edge of the insulating substrate.

Furthermore, preferably the connection wiring connects all of the biaslines, the gate lines, and the signal lines.

Still further, preferably the photoelectric conversion element includesat least an under electrode layer, an upper electrode layer, aphotoelectric conversion element semiconductor layer arranged betweenthe under electrode layer and the upper electrode layer, and a dopingsemiconductor layer arranged between the photoelectric conversionelement semiconductor layer and the upper electrode layer. The switchingelement includes at least a first electrode layer, a second electrodelayer, a switching element semiconductor layer arranged between thefirst electrode layer and the second electrode layer, and an ohmiccontact layer arranged between the switching element semiconductor layerand the second electrode layer. The connection wiring further includesthe doping semiconductor layer or the ohmic contact layer. If it isdefined that Ra is a wiring resistance of the bias line, Rb is a wiringresistance of the gate line, Rc is a wiring resistance of the signalline, Rp is a wiring resistance of the photoelectric conversion layer ofthe connection wiring between the lines under incident light, Rd is awiring resistance of the photoelectric conversion layer of theconnection wiring between the lines under no incident light, Re is awiring resistance of the doping semiconductor layer of the connectionwiring between the lines, and Rf is a wiring resistance of the ohmicsemiconductor layer of the connection wiring between the lines, thefollowing relations are satisfied:Ra, Rb, Rc<Re, Rf<RdRa, Rb, Rc<Re, Rf≦Rpor Ra, Rb, Rc≦Rp<Re, Rf

According to another aspect of the present invention, there is provideda panel for a radiographic imaging apparatus, comprising: aphotoelectric conversion substrate including a pixel area where thereare arranged a plurality of pixels each formed of a photoelectricconversion element and a switching element connected to thephotoelectric conversion element in a matrix formed on an insulatingsubstrate, a bias line for applying a bias to the photoelectricconversion element, a gate line for supplying a driving signal to theswitching element, and a signal line for reading electric chargesconverted in the photoelectric conversion element; and a conductivemember having a photoelectric conversion layer connected to at least aplurality of lines of an identical type of the bias line, the signalline, and the gate line, wherein at least a part of the conductivemember is arranged between a region including a pixel area where thereis arranged a wavelength conversion element on the insulating substrateand an edge of the insulating substrate.

In the panel for the radiographic imaging apparatus of the presentinvention, preferably the conductive member is a guard ring and there isa cutting position between the guard ring and the pixel area.

According to still another aspect of the present invention, there isprovided a method of manufacturing a radiographic imaging apparatushaving: a photoelectric conversion substrate including a pixel areawhere there are arranged a plurality of pixels each formed of aphotoelectric conversion element and a switching element connected tothe photoelectric conversion element in a matrix formed on an insulatingsubstrate, a bias line for applying a bias to the photoelectricconversion element, a gate line for supplying a driving signal to theswitching element, and a signal line for reading electric chargesconverted in the photoelectric conversion element; a wavelengthconversion element for converting radiation to light that can bedetected by the photoelectric conversion element, the wavelengthconversion element being arranged according to a region including thepixel area; and connection wiring having a photoelectric conversionlayer connected to at least a plurality of lines of an identical type ofthe bias line, the signal line, and the gate line, the method comprisingthe step of forming at least a part of the connection wiring between theregion on the insulating substrate and an edge of the insulatingsubstrate.

According to still another aspect of the present invention, there isprovided a method of manufacturing a panel for a radiographic imagingapparatus, the panel having: a photoelectric conversion substrateincluding a pixel area where there are arranged a plurality of pixelseach formed of a photoelectric conversion element and a switchingelement connected to the photoelectric conversion element in a matrixformed on an insulating substrate, a bias line for applying a bias tothe photoelectric conversion element, a gate line for supplying adriving signal to the switching element, and a signal line for readingelectric charges converted in the photoelectric conversion element; anda conductive member having a photoelectric conversion layer connected toat least a plurality of lines of an identical type of the bias line, thesignal line, and the gate line, the method comprising the step offorming at least a part of the conductive member between a regionincluding a pixel area where there is arranged a wavelength conversionelement on the insulating substrate and an edge of the insulatingsubstrate.

In this method of the present invention, preferably the conductivemember is a guard ring and the method further includes the step ofcutting the insulating substrate between the guard ring and the pixelarea.

According to the present invention, there is formed the connectionwiring or the conductive member such as the guard ring having at leastthe photoelectric conversion layer outside the pixel area, and at leasttwo lines of the Vs lines, the Vg lines, and the Sig lines can beconnected together via the conductive member, thereby preventingdeterioration in device performance and device destruction caused by astatic electricity even if the substrate is electrically charged in amanufacturing process.

Further features and advantages of the present invention will becomeapparent from the following description of exemplary embodiments (withreference to the attached drawings).

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is a schematic diagram of a radiographic imaging apparatus forexplaining a first embodiment of a radiographic imaging substrate and aradiographic imaging apparatus according to the present invention.

FIG. 2 is an equivalent circuit diagram of the radiographic imagingapparatus for explaining the first embodiment of the radiographicimaging substrate and the radiographic imaging apparatus according tothe present invention.

FIG. 3 is an enlarged view of a portion close to a cut section of theradiographic imaging substrate for explaining the first embodiment ofthe radiographic imaging substrate and the radiographic imagingapparatus according to the present invention.

FIG. 4A is a cross section taken on line A-A of FIG. 3 for explainingthe first embodiment of the radiographic imaging substrate and theradiographic imaging apparatus according to the present invention.

FIG. 4B is a cross section taken on line B-B of FIG. 3 for explainingthe first embodiment of the radiographic imaging substrate and theradiographic imaging apparatus according to the present invention.

FIG. 5 is a schematic diagram of a radiographic imaging apparatus forexplaining a second embodiment of a radiographic imaging substrate and aradiographic imaging apparatus according to the present invention.

FIG. 6 is an equivalent circuit diagram of the radiographic imagingapparatus for explaining the second embodiment of the radiographicimaging substrate and the radiographic imaging apparatus according tothe present invention.

FIG. 7 is an enlarged view of a portion close to a cut section of theradiographic imaging substrate for explaining the second embodiment ofthe radiographic imaging substrate and the radiographic imagingapparatus according to the present invention.

FIG. 8A is a cross section taken on line A-A of FIG. 7 for explainingthe second embodiment of the radiographic imaging substrate and theradiographic imaging apparatus according to the present invention.

FIG. 8B is a cross section taken on line B-B of FIG. 7 for explainingthe second embodiment of the radiographic imaging substrate and theradiographic imaging apparatus according to the present invention.

FIG. 9 is a schematic diagram of a radiographic imaging apparatus forexplaining a third embodiment of a radiographic imaging substrate and aradiographic imaging apparatus according to the present invention.

FIG. 10 is an enlarged view of a portion close to a cut section of theradiographic imaging substrate for explaining the third embodiment ofthe radiographic imaging substrate and the radiographic imagingapparatus according to the present invention.

FIG. 11A is a cross section taken on line A-A of FIG. 10 for explainingthe third embodiment of the radiographic imaging substrate and theradiographic imaging apparatus according to the present invention.

FIG. 11B is a cross section taken on line B-B of FIG. 10 for explainingthe third embodiment of the radiographic imaging substrate and theradiographic imaging apparatus according to the present invention.

FIG. 12 is a schematic diagram for explaining an application in whichthe radiographic imaging substrate and the radiographic imagingapparatus of the present invention are applied to an X-ray diagnosticapparatus.

FIG. 13 is a schematic diagram of a conventional radiographic imagingsubstrate and radiographic imaging apparatus.

FIG. 14 is an equivalent circuit diagram of the conventionalradiographic imaging substrate and radiographic imaging apparatus.

FIG. 15 is a plan view of the conventional radiographic imagingsubstrate and radiographic imaging apparatus.

FIG. 16 is a cross section of a single pixel of the conventionalradiographic imaging substrate and radiographic imaging apparatus.

FIG. 17 is an enlarged view of a portion close to a cut section of theconventional radiographic imaging substrate.

DESCRIPTION OF THE EMBODIMENTS

A preferred embodiment of the present invention will be described indetail in accordance with the accompanying drawings.

First Embodiment

Hereinafter, a first embodiment of a radiographic imaging substrate anda radiographic imaging apparatus according to the present invention willbe described with reference to accompanying drawings.

Referring to FIGS. 1, 2, 3, and 4, there are shown a schematic diagramof the radiographic imaging apparatus of the present invention, anequivalent circuit diagram thereof, an enlarged view of a portion closeto a cut section of the radiographic imaging substrate (insulatingsubstrate), and cross sections of a single pixel and connection wiring,respectively. Regarding FIG. 4, FIG. 4A shows the cross section of thesingle pixel (on line A-A of FIG. 3) and FIG. 4B shows the cross sectionof the connection wiring (on line B-B of FIG. 3).

The radiographic imaging apparatus of the present invention isconstructed of a combination of a radiographic imaging substrate, onwhich there are arranged optical sensors of MIS-TFT structure eachformed of an MIS-type photoelectric conversion element and a switchingTFT, and phosphors for converting radiation to visible light, and othersincluding a principle of driving are the same as those of theconventional art. Therefore, their description is omitted here.

As shown, gate lines (Vg lines) are formed in a first electrode layer 11in a pixel area and in a second electrode layer in a TCP-D connectionpad portion 10 and are connected together via contact holes. All of biaslines (Vs lines), gate lines (Vg lines), and signal lines (Sig lines)are connected together via connection wiring 3. The connection wiring 3is arranged in a region between the region 11 where there is formed aphosphor layer 19 including a pixel area 2 and an edge of the insulatingsubstrate.

As shown in FIG. 3, the connection wiring 3 is formed of a firstsemiconductor layer 13 and a doping semiconductor layer 14 similarly tothe MIS-type photoelectric conversion element. Moreover, a hole blockinglayer and an ohmic contact layer are the similar doping semiconductorlayers 14. The doping semiconductor layer 14 is formed of an n-typesemiconductor into which phosphorus as impurity is introduced. If thephotoelectric conversion element is of PIN type, the dopingsemiconductor layer 14 is formed of a p-type semiconductor into whichboron is introduced.

It should be noted here that the first semiconductor layer 13 has acharacteristic of a high resistance under no incident light and of a lowresistance under incident light due to holes and electrons generated inthe layer.

Therefore, if it is defined that Ra is a wiring resistance of a biasline (Vs line), Rb is a wiring resistance of a gate line (Vg line), Rcis a wiring resistance of a signal line (Sig line), Rp is a wiringresistance of the first semiconductor layer 13 of the connection wiring3 between the lines under incident light, Rd is a wiring resistance ofthe first semiconductor layer 13 of the connection wiring between thelines under no incident light, and Re is a wiring resistance of thedoping semiconductor layer 14, the following relations are satisfied:Ra, Rb, Rc<Re<RdRa, Rb, Rc<Re≦Rp or Ra, Rb, Rc≦Rp<Re

Therefore, for example, even if the insulating substrate 1 iselectrically charged in a manufacturing process, the resistance of theconnection wiring 3 is low since the product is manufactured in anenvironment in which light is incident on the insulating substrate 1 anda potential difference between the lines is hard to occur since all ofthe bias lines (Vs lines), the gate lines (Vg lines), and the signallines (Sig lines) are connected together via the connection wiring 3.Therefore, it is possible to prevent static electricity generated in themanufacturing process from passing through the lines and damaging thephotoelectric conversion elements or the TFTs.

Moreover, the radiographic imaging apparatus with the radiographicimaging substrate 1 has the phosphor layer 19 formed on the regionincluding the pixel area 2 as shown in FIG. 4 and has no phosphor layer19 on the region where the connection wiring 3 is formed. Therefore, inthe radiographic imaging apparatus housed in a cabinet (not shown), noexternal light nor light emitted from the phosphor layer 19 will beincident on the connection wiring 3, and thus the resistance of theconnection wiring 3 is high and they have no influence on the operationof the radiographic imaging apparatus.

Furthermore, a panel inspection using TCP connection pads 9 and 10 isalso performed in an environment in which no light is incident on thepanel, and therefore the light has no influence on the inspection.

As stated above, the connection wiring 3 having at least a photoelectricconversion layer (first semiconductor layer 13) is formed in a regionbetween the region where there is formed the phosphor layer 19 includingthe pixel area 2 and the edge of the insulating substrate 1 and the biaslines (Vs lines), the gate lines (Vg lines), and the signal lines (Siglines) are connected together via the connection wiring 3, therebyoffering an effect of preventing deterioration in device performance anddevice destruction from being caused by static electricity even if thesubstrate is electrically charged in a manufacturing process.

While the same doping semiconductor layers 14 have been used as the holeblocking layer and the ohmic contact layer in this embodiment, eitherthe hole blocking layer or the ohmic contact layer can be used as theconnection wiring 3 if these layers are separate from each other.

Moreover, while the MIS-type photoelectric conversion element has beenused as the semiconductor conversion element in this embodiment, thePIN-type photoelectric conversion element is also applicable. Regardingthe pixel structure, either type of the following is applicable: a flattype in which a semiconductor conversion element and a switching elementare formed in an identical layer and a stacked type in which asemiconductor conversion element is formed on a layer where a switchingelement is formed.

Second Embodiment

The following describes a second embodiment of a radiographic imagingsubstrate and a radiographic imaging apparatus according to the presentinvention with reference to accompanying drawings.

Referring to FIGS. 5, 6, 7, and 8, there are shown a schematic diagramof the radiographic imaging apparatus of the present invention, anequivalent circuit diagram thereof, an enlarged view of a portion closeto a cut section of the radiographic imaging substrate (insulatingsubstrate), and cross sections of a single pixel and a guard ring,respectively. Regarding FIG. 8, FIG. 8A shows the cross section of thesingle pixel (on line A-A of FIG. 7) and FIG. 8B shows the cross sectionof the guard ring (on line B-B of FIG. 7).

As shown, references P11 to P44 designate photoelectric conversionelements and references T11 to T44 designate first switching elements(TFTs). As shown, the photoelectric conversion elements P11 to P44 areconnected to bias lines Vs1 to Vs4 and a first readout device 22 and asecond readout device 23 apply given biases to them. Gate electrodes ofthe TFTs are connected to gate lines Vg1 to Vg4 and the gate lines areconnected to a first gate drive unit 20 and a second gate drive unit 21.Moreover, as shown, source or drain electrodes of the TFTs are connectedto common signal lines Sig1 to Sig8. The Sig1 to Sig4 are connected tothe first readout device 22 and similarly Sig5 to Sig8 are connected tothe second readout device 23.

The radiographic imaging apparatus of the present invention isconstructed of a combination of a radiographic imaging substrate, onwhich there are arranged optical sensors of MIS-TFT structure eachformed of an MIS-type photoelectric conversion element and a switchingTFT, and phosphors for converting radiation to visible light, and othersincluding a principle of driving are the same as those of theconventional art. Therefore, their description is omitted here.

As shown, in the radiographic imaging substrate of this embodiment, gatelines are formed in a first electrode layer 11 in a pixel area and in asecond electrode layer in a TCP-D connection pad portion 10 and areconnected together via contact holes. In addition, a guard ring 24 isformed in a region between a region where there is formed a phosphorlayer 19 including a pixel area 2 and an edge of an insulating substrate1. The bias lines (Vs lines), the gate lines (Vg lines), and the signallines (Sig lines) are connected to the guard ring 24. In this regard, itis assumed that the guard ring is a conductive member formedsubstantially in a ring shape around the pixel area for the purpose ofpreventing an electrostatic destruction of the pixel area in the presentinvention.

Furthermore, as shown in the cross section, the guard ring 24 is formedof a first electrode layer 11, a first insulating layer 12, and a firstsemiconductor layer 13 similarly to the MIS-type photoelectricconversion element, with the lines connected to the guard ring 24 via adoping semiconductor layer 14 and the doping semiconductor layer 14arranged separately from the lines.

It should be noted here that the first semiconductor layer 13 has acharacteristic of a high resistance under no incident light and of a lowresistance under incident light due to holes and electrons generated inthe layer, similarly to the first embodiment.

Therefore, for example, even if the insulating substrate 1 iselectrically charged in a manufacturing process, the resistance of theconnection wiring is low since the product is manufactured in anenvironment in which light is incident on the insulating substrate 1 anda potential difference between the lines is hard to occur since all ofthe bias lines (Vs lines), the gate lines (Vg lines), and the signallines (Sig lines) are connected together via the guard ring 24.Therefore, it is possible to prevent static electricity generated in themanufacturing process from passing through the lines and damaging thephotoelectric conversion elements or the TFTs.

Furthermore, a panel inspection using TCP connection pads 9 and 10 isperformed in an environment in which no light is incident on the panel,and therefore the light has no influence on the inspection.

Furthermore, as shown in FIG. 7, there is provided a cut section(indicated by a dashed line in FIG. 7) of the insulating substrate 1between the pixel area 2 and the guard ring 24. Therefore, on theradiographic imaging substrate after cutting, the lines are separatedfrom each other and this arrangement has no influence on the operationof the radiographic imaging apparatus.

As stated above, the guard ring 24 having at least the photoelectricconversion layer (first semiconductor layer 13) is formed in a regionbetween the region where there is formed the phosphor layer 19 includingthe pixel area 2 and the edge of the insulating substrate 1. It is thenconnected to one of the bias lines (Vs lines), the gate lines (Vglines), and the signal lines (Sig lines) and a cut section of theinsulating substrate is provided between the pixel area 2 and the guardring 24, thereby offering an effect of preventing deterioration indevice performance and device destruction from being caused by staticelectricity even if the substrate is electrically charged in amanufacturing process.

While the lines and the guard ring 24 have been connected via the holeblocking layer (doping semiconductor layer 14) in this embodiment, itcan be an ohmic contact layer (doping semiconductor layer 14) forforming a switching element.

Moreover, while the MIS-type photoelectric conversion element has beenused as the semiconductor conversion element in this embodiment, thePIN-type photoelectric conversion element is also applicable. Regardingthe pixel structure, either type of the following is applicable: a flattype in which a semiconductor conversion element and a switching elementare formed in an identical layer and a stacked type in which asemiconductor conversion element is formed on a layer where a switchingelement is formed.

Third Embodiment

The following describes a third embodiment of a radiographic imagingsubstrate and a radiographic imaging apparatus according to the presentinvention with reference to accompanying drawings.

Referring to FIGS. 9, 10, and 11, there are shown a schematic diagram ofthe radiographic imaging apparatus of the present invention, an enlargedview of a portion close to a cut section of the radiographic imagingsubstrate (an insulating substrate), and cross sections of a singlepixel and connection wiring 1, respectively. Regarding FIG. 11, FIG. 11Ashows the cross section of the single pixel (on line A-A of FIG. 10) andFIG. 11B shows the cross section of the connection wiring 1 (on line B-Bof FIG. 10). An equivalent circuit is the same as for the secondembodiment and therefore its description is omitted here.

The radiographic imaging apparatus of the present invention isconstructed of a combination of a radiographic imaging substrate, onwhich there are arranged optical sensors of MIS-TFT structure eachformed of an MIS-type photoelectric conversion element and a switchingTFT, and phosphors for converting radiation to visible light, and othersincluding a principle of driving are the same as those of theconventional art. Therefore, their description is omitted here.

Regarding the layer structure of the radiographic imaging apparatus ofthis embodiment, as shown in FIG. 10, the TFT includes a gate electrode(first electrode layer 11), a gate insulating layer (first insulatinglayer 12), a first semiconductor layer 13, an ohmic contact layer(doping semiconductor layer 14), and a source-drain electrode (secondelectrode layer 15). Each gate line (Vg line) is connected to the firstelectrode layer 11 where the gate electrode of the TFT is formed andeach signal line (Sig line) is connected to the second electrode layer15 where the source-drain electrode is formed. A second insulating layer16 is disposed on the TFT and an MIS-type photoelectric conversionelement is formed thereon. The MIS-type photoelectric conversion elementis formed of a under electrode (third electrode layer 27), an insulatinglayer (third insulating layer 28), a photoelectric conversion layer(second semiconductor layer 29), a hole blocking layer (second dopingsemiconductor layer 30), a bias line (fourth electrode layer 31), and anupper electrode (transparent electrode layer 32), with the underelectrode connected to the source-drain electrode of the TFT. Thephotoelectric conversion element and the TFT are then coated with andprotected by a fourth insulating layer 33 and an organic protectivelayer 17.

In the radiographic imaging substrate of this embodiment, bias lines (Vslines) in both end portions connected to a first readout device 22 andto a second readout device 23 are connected to all gate lines (Vg lines)via first connection wiring 25 in a region where there is formed aphosphor layer 19 including a pixel area 2. In this regard, the gatelines (Vs lines) are connected via Vs connection wiring 25′ in a regionoutside the pixel area 2 and within a region where a phosphor layer isformed. In other words, in this embodiment, all the Vs lines areconnected to all the Vg lines via the first connection wiring 25 and theVs connection wiring 25′ in the region where there is formed thephosphor layer 19 including the pixel area 2. Moreover, all the gatelines (Vg lines) are connected together via the first connection wiring25 in a region between the region where there is formed the phosphorlayer 19 including the pixel area 2 and an edge of the insulatingsubstrate 1. Each bias line (Vg line) and each signal line (Sig line)form a contact hole outside the pixel area 2 and connected to the fourthelectrode layer 31 forming the bias line (Vg line) via the thirdelectrode layer 27, thereby forming TCP connection pads 9 and 10 in thefourth electrode layer 31. Furthermore, as shown in the cross section,the first connection wiring 25 is formed of the first semiconductorlayer 13 and the ohmic contact layer (doping semiconductor layer 14)similarly to the TFT. While second connection wiring 26 is divided atcontact holes of the bias lines (Vg lines) here, it may not be divided.

It should be noted here that the first semiconductor layer 13 has acharacteristic of a high resistance under no incident light and of a lowresistance under incident light due to holes and electrons generated inthe layer. Therefore, if it is defined that Ra is a wiring resistance ofa bias line (Vs line), Rb is a wiring resistance of a gate line (Vgline), Rp is a wiring resistance of the first semiconductor layer 13 ofeach connection wiring under incident light, Rd is a wiring resistanceof the first semiconductor layer 13 between the gate lines under noincident light, and Rf is a wiring resistance of the ohmic contact layernot divided, the following relations are satisfied:Ra, Rb<Rf<RdRa, Rb<Rf≦RpSince the connection wiring has the relation Rf<Rp between the gatelines, the first connection wiring and the second connection wiring arearranged to achieve Rf≦Rp.

Therefore, for example, even if the insulating substrate 1 iselectrically charged in a manufacturing process, the resistance of theconnection wiring 3 is low since the product is manufactured in anenvironment in which light is incident on the insulating substrate 1 anda potential difference between the lines is hard to occur since all ofthe bias lines (Vs lines) and the gate lines (Vg lines) are connectedvia the first connection wiring 25, the Vs connection wiring 25′, andthe second connection wiring 26. Therefore, it is possible to preventstatic electricity generated in the manufacturing process from passingthrough the lines and damaging the photoelectric conversion elements orthe TFTs.

Moreover, the radiographic imaging apparatus with the radiographicimaging substrate has the phosphor layer 19 formed on the regionincluding the pixel area 2 as shown in FIG. 10 and has no phosphor layer19 on the region where the second connection wiring 26 is formed.Therefore, in the radiographic imaging apparatus housed in a cabinet(not shown), no external light nor light emitted from the phosphor layer19 will be incident on the second connection wiring 26, and thus theresistance of the second connection wiring 26 is high and practicallythe connection wiring has the relations Rf<Rd and Rf<Rp between the gatelines. Therefore, they have no influence on the operation of theradiographic imaging apparatus.

As stated above, a part of the connection wiring (the second connectionwiring 26 in this embodiment) having at least the photoelectricconversion layer (first semiconductor layer 13) is formed in the regionbetween the region where there is formed the phosphor layer 19 includingthe pixel area 2 and the edge of the insulating substrate 1, and thebias lines (Vs lines) and the gate lines (Vg lines) are connectedtogether via the connection wiring (the first connection wiring 25, theVs connection wiring 25′, and the second connection wiring 26), therebyoffering an effect of preventing deterioration in device performance anddevice destruction from being caused by static electricity even if thesubstrate is electrically charged in a manufacturing process.

Moreover, while the MIS-type photoelectric conversion element has beenused as the semiconductor conversion element in this embodiment, thePIN-type photoelectric conversion element is also applicable. Regardingthe pixel structure, either type of the following is applicable: astacked type in which a semiconductor conversion element is formed on alayer where a switching element is formed and a flat type in which asemiconductor conversion element and a switching element are formed inan identical layer.

Fourth Embodiment

Referring to FIG. 12, there is shown an application in which aradiographic imaging substrate and a radiographic imaging apparatusaccording to the present invention are applied to an X-ray diagnosticsystem.

X rays 6060 generated in an X-ray tube 6050 pass through a chest 6062 ofa patient or subject 6061 and impinge on a radiographic imagingapparatus 6040 provided with a scintillator in its upper portion.

The incident X rays include information on the inside of the body of thepatient 6061. The scintillator emits light in response to the incidenceof the X rays and photoelectrically converts them to acquire electricalinformation. This information is subjected to digital conversion andthen to image processing using an image processor 6070 as signalprocessing means, whereby it can be observed on a display 6080 asdisplay means in a control room.

Furthermore, the information can be transferred to a remote location byusing transmission processing means such as a telephone line 6090 andcan be displayed on a display 6081 as display means in a doctor room inanother place or stored in recording means such as an optical disk,whereby a doctor in a remote location can diagnose the patient.

Still further, a film processor 6100 as the recording means can recordthe information into a film 6110 as a recording medium.

While the present invention has been described with reference toexemplary embodiments, it is to be understood that the invention is notlimited to the disclosed embodiments. On the contrary, the invention isintended to cover various modifications and equivalent arrangementsincluded within the spirit and scope of the appended claims. The scopeof the following claims is to be accorded the broadest interpretation soas to encompass all such modifications and equivalent structures andfunctions.

This application claims priority from Japanese Patent Application No.2004-177009 filed Jun. 15, 2004, which is hereby incorporated byreference herein.

1. A radiographic imaging apparatus, comprising: a photoelectricconversion substrate including a pixel area where there are arranged aplurality of pixels each having a photoelectric conversion element and aswitching element connected to said photoelectric conversion element ina matrix formed on an insulating substrate, wherein said photoelectricconversion element is arranged over said switching element, and aplurality of lines; a wavelength conversion element for convertingradiation to light that can be detected by said photoelectric conversionelement, said wavelength conversion element being arranged according toa region including the pixel area; and a semiconductor layer connectedto the plurality of lines, wherein at least a part of said semiconductorlayer is arranged between said region on the insulating substrate and anedge of said insulating substrate, wherein said switching elementincludes at least a first electrode layer, a second electrode layer, afirst semiconductor layer arranged between said first electrode layerand said second electrode layer, and a first doping semiconductor layerarranged between said first semiconductor layer and said secondelectrode layer; the photoelectric conversion element includes at leastan under electrode layer, an upper electrode layer, a secondsemiconductor layer arranged between said under electrode layer and saidupper electrode layer, and a second doping semiconductor layer arrangedbetween said second semiconductor layer and said upper electrode layer;and an insulating layer is arranged between said switching element andsaid photoelectric conversion element.
 2. A radiographic imaging system,comprising: a radiographic imaging apparatus according to claim 1;signal processing means for processing signals from said radiographicimaging apparatus as an image; recording means for recording signalsfrom said signal processing means; display means for displaying signalsfrom said signal processing means; and transmission processing means fortransmitting signals from said signal processing means.
 3. A panel for aradiographic imaging apparatus, comprising: a photoelectric conversionsubstrate including a pixel area where there are arranged a plurality ofpixels each having a photoelectric conversion element and a switchingelement connected to said photoelectric conversion element in a matrixformed on an insulating substrate, wherein said photoelectric conversionelement is arranged over said switching element, and a plurality oflines; and a semiconductor layer connected to said plurality of lines,wherein at least a part of said semiconductor layer is arranged betweena region including said pixel area where there should be arranged awavelength conversion element on said insulating substrate and an edgeof said insulating substrate, wherein said switching element includes atleast a first electrode layer, a second electrode layer, a firstsemiconductor layer arranged between said first electrode layer and saidsecond electrode layer, and a first doping semiconductor layer arrangedbetween said first semiconductor layer and said second electrode layer;the photoelectric conversion element includes at least an underelectrode layer, an upper electrode layer, a second semiconductor layerarranged between said under electrode layer and said upper electrodelayer, and a second doping semiconductor layer arranged between saidsecond semiconductor layer and said upper electrode layer; and aninsulating layer is arranged between said switching element and saidphotoelectric conversion element.